78 RASEN · TURF · GAZON 4/2024 bei anhaltender Dürre eine Regeneration des Rotschwingels ausbleibt und, sobald Wasser wieder verfügbar wird, sich Jährige Rispe (Poa annua) in den verbleibenden Lücken etabliert. Die Autoren empfehlen Greenkeepern, die Artenzusammensetzung an ihrem Standort zu überdenken und auf ihren trockenheitsempfindlichsten Fairways kleine Versuche mit Saatgutmischungen, die Rohrschwingel (Festuca arundinacea) und/oder tetraploides Deutsches Weidelgras (Lolium perenne) enthalten, anzulegen. Weiterhin muss auch geklärt werden, inwieweit die derzeit in Europa verfügbaren Rohrschwingelsorten Schnitthöhen vertragen von 15 bis 20 mm vertragen. Introduction The STERF-project ‘FAIR-WATER: Towards better drought resistance and reduced water consumption on golf course fairways’ started in 2023, and we have previously reported results from subproject (SP) 2 in which we explore to what extent drought can be prevented by the application of soil surfactants. (See: https://sterf. org/wp-content/uploads/2024/09/ FAIR-WATER-article-about-projectk-.pdf ). The purpose of this article is to present preliminary results from SP 1 where we study the ability of various grass species and varieties to maintain turfgrass coverage and quality during prolonged drought periods, and to recover rapidly once the drought period is over. Methods At the start of ‘FAIR-WATER’ in 2023 we invited turfgrass breeders and seed companies to enter their supposedly most drought resistant varieties into a drought trial to be conducted under a rainout shelter at NIBIO Landvik, Norway. The invitation resulted in 42 varieties, including the same reference varieties as used in SCANTURF variety testing (Table 1). The experiment has four reps., plot size 0.9 x 0.9 = 0.81 m2 and was seeded in May 2023. It is placed on a sand-dominated soil (88 % sand, 8 % silt, 4 % clay, 4 % organic matter) that was filled up under the rainout shelter to a depth of 80 cm during the winter 2022-23 and tile-drained before seeding in May. According to the experimental protocol, all plots should have at least 90 % coverage before starting the first drought period in 2024. However, the grow-in of Kentucky bluegrass, hard fescue, tall fescue and strong creeping red fescue in 2023 was so slow that these species, despite no winter damage, had only about 80 % coverage at the start of the drought period on 30 April 2024. On this day, the 4 m high rainout shelter was covered with plastic, and the experiment irrigated to field capacity before entering an eight week drought period (30 Apr. – 25 June) with no irrigation at Photo 1: Digital images of all plots were taken in a lightbox 1-2 times per week during the entire experiment. (Photo: T.S. Aamlid) Figure 2: Turfgrass quality (1-9) of eleven grass species (including subspecies of red fescue and the distinction between diploid and tetraploid ryegrass) during eight weeks of drought and three weeks of recovery. Means of 2-8 varieties within each species / subspecies. Figure 1: Percent coverage of eleven grass species (including subspecies of red fescue and the distinction between diploid and tetraploid ryegrass) as determined by ‘Turf Analyzer’ from digital images taken during eight weeks of drought and three weeks of recovery. Means of 2-8 varieties within each species / subspecies.
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